| Presenter Name: | David Falconer |
| Authors: | David Falconer, Ron Moore, Abdulnasser Barghouty, and Igor Khazanov |
| Title: | Forecasting Solar Drivers of Severe Space Weather from SOHO/MDI Magnetograms of Active Regions |
| Abstract: |
We present the performance of our method of forecasting from a SOHO/MDI magnetogram of a sunspot active region the chance that in the coming day or so the active region’s magnetic field will explode to produce a severe-space-weather driver or a severe-space-weather event of a specified type and strength. The method is based on whole-active-region magnetic quantities measured from the magnetogram together with the observed fraction of previously observed similar active regions that produced the specified class of event in the specified time window. We have collected a data base of ~50,000 active-region magnetograms of ~1500 active regions observed within 0.5 RSun (30 heliocentric degrees) of disk center. Each active-region magnetogram is extracted from the full-disk MDI magnetogram by an automated code. The 96-minute cadence of the MDI magnetograms tracks the magnetic evolution of each active region across the 0.5-RSun central disk. From each active-region magnetogram, we measure (1) a magnetic quantity that is a measure of the active region’s magnetic size and (2) another magnetic quantity that is a gauge of the active region’s free magnetic energy. The free energy is the magnetic energy in excess of the potential-field energy. Only free magnetic energy can be released in a CME and/or flare eruption. We use the NOAA Flare/CME/SEP-Event catalogs to compile each active region’s history of production of flares, CMEs, and SEP events. We find that, for each class of event, the fraction of active regions in our data base that produce this event in any given forward time window increases with the free-magnetic-energy gauge as a power law. We also find that each class of event is produced only by active regions having magnetic-size measure larger than a threshold value that depends on the class of event. We are using these aspects of our data base to develop a forecasting tool for NASA’s Space Radiation Analysis Group (SRAG) under a NASA Technical Excellence Initiative (TEI) award for transitioning our research codes to forecasting tools. We are presently evaluating the degree to which each of several other active-region magnetic measures or other solar conditions, in combination with the free-magnetic-energy gauge, provide a stronger prediction of active-region event productivity than does the free-energy-gauge alone. This work is funded by the NASA Technical Excellence Initiative Program, by the AFOSR MURI Program, by the NASA LWS TR&T Program, and by the NSF SHINE Program. |